Добијање производа додатне вредности од отпадне биомасе

Енергетска транзиција подразумева примену правилног управљања отпадним биомасама које обухвата њено смањење, поновну употребу, рециклирање, добијање енергије и/или одлагање. Наука нуди решења за ефикасну примену поновне употребе и рециклирања, где се добијају производи додатне вредности. У Србији, према проценама, у врстама отпадних биомаса доминирају жетвени остаци (10.140.268 t годишње) и остаци резидбе воћа (74.329 t годишње) а следе стајњак, отпадни материјал из прерадне индустрије и биоразградиви комунални отпад. Биопроцесовање (употреба микроба и ензима) представља најприхватљивије решење заштите животне средине, где се из отпадне биомасе добијају вредни производи (пребиотици, биоактивни пептиди, антибиотици, терпеноиди, алкалоиди, итд.) широке примене у храни, лековима и козметици. Из отпадног клипа кукуруза (кога у Србији има 1.073.780 t годишње) добијају се пребиотици, одобрени за употребу у исхрани. Искоришћени компост за гајење шампињона је погодан супстрат за микробиолошко добијање индустријски значајних ензима (амилазе, целулазе, ксиланазе). Постоје примери индустрије где се из дрвних остатака (којих има у Србији 700.000 m3 годишње) поред етанола добијају и ацеталдехид, сирћетна киселина и етилацетат. Екстракцијом из остатака индустрије прераде воћа, поврћа и винове лозе се могу добити полифеноли (антиоксиданси) и други вредни производи. Максимална искористљивост отпадне биомасе може се постићи комбиновањем метода биопроцесовања за добијање производа додатне вредности са добијањем енергије (биогаса, биоетанола).Predavanje po pozivu / Invited lectur

Diffusion screening method for estimation potential fungal producers of xylanase responsible for xylooligosaccharides production

Wild-type microorganisms from the environment represent a wide source of potential enzyme producers. In order to determine whether an isolated microorganism produces an enzyme of interest, various screen tests have been developed. A new screening method for detection of endo and exo-xylanase activity including short time growth of fungal strains on a minimal medium containing xylan (inducible substrate) as a carbon source is developed and used for testing 58 fungal isolates from genus Aspergillus. The test is based on the diffusion of samples (fermentation extracts) in polyacrylamide gel incorporated by xylan. Endoxylanase activity is detected as enlightenment in the gel after staining of xylan with Congo Red. Exoxylanase activity was visualized as a precipitate after staining of reduction oligosaccharide ends with NBT. Selected isolate A. tubigensis was grown on SSF where corn cob served as an inducible substrate. In order to examine the influence of nitrogen sources on endoxylanase production and fungal growth, two sources (peptone and urea) were varied in 3 concentrations (1, 5 and 10 g/L). There were statistically significant differences in the obtained activities. The increase in activity compared to the screening medium was ~250 times. The obtained enzymes with high specific activity were further used for the production of xylooligosaccharides in high yield which showed that the selection of strain A. tubingensis was good

The Supplementary data for: "Fungal oxidative and hydrolyzing enzymes as designers in the biological production of dietary fibers from triticale"

FTIR spectra of IDFT treatment with fungal enzymatic complex.The Supplementary data for: Margetić, A., Stojanović, S., Ristović, M., & Vujčić, Z. M. (2021). Fungal oxidative and hydrolyzing enzymes as designers in the biological production of dietary fibers from triticale. LWT - Food Science and Technology, Elsevier., 145, 111291. [https://doi.org/10.1016/j.lwt.2021.111291]The published version of the article: [https://cer.ihtm.bg.ac.rs/handle/123456789/4540

In situ production of xylooligosaccharides by Aspergillus tubingensis from corn cob

Xylooligosaccharides (XOS) are prebiotic, functional food ingredients, with biological benefits such as immunomodulatory and anti-inflammatory properties, anticancer and antioxidant activity. Usually, XOS are produced from xylan by the combination of pre-treatment, enzymatic, chemical and/or auto-hydrolytic methods. Fungal xylanases are the most suitable for XOS production. Xylan rich agro-industrial wastes (corn cob is one of them) are used as a substrate for fungal xylanase production and as start material for xylan extraction. In situ XOS production by fungal growth on xylan rich medium represents an attractive and advantageous approach but insufficient described till now. This method has many advantages over the others because bypasses the extraction and purification of xylan and enzymes, it is environmentally friendly, low cost and time-consuming. This study demonstrated A. tubingensis FAT35 has a great capacity for the synthesis of XOS using corn cob as a substrate in solid state fermentation (SSF). Obtained XOS, during the fungal growth, were characterized by TLC and HPLC. Significant antioxidant potential was shown by antioxidant tests (ORAC, DPPH and FRAP). The obtained XOS are suitable to be a functional food additive and are obtained in the simplest way that is both environmentally and economically suitable

Exoinulinase gene expression in Aspergillus welwitschiae FAW1 induced by different carbon sources

Fungal inulinases have wide application in industrial biotechnology, and it is presumed that their expression is regulated at the transcriptional level via promoter. It is also known that different sugars have an inducing effect on gene expression in fungal genome, including inulinases. Aim of this work was to determine which of the sugars used in growth medium, as the only carbon source, induce the extracellular exoinulinase gene inuE expression in Aspergillus welwitschiae FAW1. Inulin, rafinose, sucrose, glucose and fructose were used as carbon sources, and expression of inuE was monitored during 72 h of cultivation (tested after 24, 36, 48 and 72 h). Both, presence of mRNA in the mycelia and extracellular enzyme activity in the growth media were monitored. Interestingly, obtained results showed that inuE was induced by fructose, sucrose and rafinose and not by inulin. In all cases, the highest mRNA was detected after 24 h of cultivation, while extracellular exoinulinase activity increased from 24 h with a peak in 72 h. Further experiments are necessary for a comprehensive understanding of the regulation mechanisms of AweinuE promoter for its more purposeful application in biotechnology

Cloning, overexpression and characterization of a thermostable endo-1,4-beta-xylanase from Anoxybacillus vranjensis ST4

This research deals with the characterization of a thermostable endo-1,4-beta-xylanase enzyme from Anoxybacillus vranjensis ST4, a thermophilic bacterium isolated from Vranjska Banja hot spring, Serbia. The enzyme shows a high degree of identity with the same type of enzyme from other species of the genera Anoxybacillus (97%), Geobacillus (74%) and Paenibacillus (65%). The gene for endo-1,4-beta-xylanase from the thermophilic strain ST4 was cloned into the pQE_Ek expression vector and successfully expressed and purified from the Escherichia coli M15[pREP4]. The study encompasses recombinant production, purification, and the comprehensive characterization of the enzymatic properties of endo-1,4-beta-xylanase. This is the first successful overexpression, purification and characterization of a recombinant thermostable endo-1,4-beta-xylanase enzyme from Anoxybacillus. With a monomeric structure of 38.7 kDa, the enzyme demonstrates peak activity at 70°C and pH 6.5. Notably, it exhibits remarkable stability across a wide pH range and at high temperatures, rendering it suitable for diverse industrial applications. Investigation into the enzyme’s kinetic parameters, substrate specificity, and its ability to degrade xylan into high-energy value products further enhances understanding of its biotechnological potential. These findings underscore the significance of thermophilic bacteria and their thermostable enzymes in various industrial processes

Highly active xylanase used in juice clarification

Xylan makes a significant part of cereals and fruits, which are used in the food industry. Therefore, enzymes that hydrolyze xylan (xylanases) have found application in the modification of cereal-based food, improving the digestibility of animal feed, and improving the texture of bakery products. In the juice industry, the main problems are turbidity, viscosity, and sedimentation during standing, which are caused by polysaccharides present in fruit (pectins, cellulose, and hemicellulose (xylan)). Pineapple, apple, orange, and tomato have a high content of hemicellulose, so xylanases are suitable for improving the properties of these juices. The Aspergillus tubingensis FAT 35 strain (considered safe for use in the food industry) growing on SSF medium composed of corn cob produced a high level of xylanase enzyme (4.03 U∕mL) and not that high pectinase (1.02 U∕mL) and cellulase (1.43 U∕mL) activities at pH 3 which is pH of freshly prepared apple, pineapple and organge juice.. The fermentation extract was used for clarification of pineapple, apple, and orange juice and for increasing the filtration rate and yield of these juices. Results indicate that A. tubigensis xylanase could be used for clarification and improvement of properties of juices of fruits that contain hemicellulose in high proportion

Supplementary data for the article: Bradan, G.; Cobeljic, B.; Pevec, A.; Turel, I.; Milenkovic, M.; Radanovic, D.; Sumar-Ristovic, M.; Adaila, K.; Milenkovic, M.; Andelkovic, K. Synthesis, Characterization and Antimicrobial Activity of Pentagonal-Bipyramidal Isothiocyanato Co(II) and Ni(II) Complexes with 2,6-Diacetylpyridine Bis(Trimethylammoniumacetohydrazone). J. Coord. Chem. 2016, 69 (5), 801–811. https://doi.org/10.1080/00958972.2016.1139702

Supplementary material for: [https://doi.org/10.1080/00958972.2016.1139702]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1907]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3635

Screening of pectinase-producing Aspergillus spp. for use in strawberry juice clarification

U ovom radu urađen je skrining sojeva Aspergillus spp. koji proizvode pektinaze fermentacijom u tečnom medijumu, a koje su efikasne u izbistravanju soka od jagode. Endo-pektinaze su detektovane difuzionim testom, a ukupna pektinazna aktivnost određena je DNS metodom. Izbistravanje soka nakon tretmana pektinazama određeno je merenjem transmitancije na 660 nm, a povećanje prinosa soka izmereno je centrifugiranjem. Dobijeni rezultati su pokazali da su ove pektinaze visokoefikasne za tretman soka od jagode u poređenju sa komercijalnim pektinaznim preparatom Lafase Fruit.In this work, the screening of Aspergillus spp which produce pectinases by fermentation in a liquid medium was performed, as pectinases are effective in clarifying strawberry juice. Endo-pectinases were detected by the diffusion assay, and total pectinase activity was determined by the DNS method. The clarification of juice after pectinase treatment was determined by measuring the transmission at 660 nm, and an increase in juice yield was measured by centrifugation. The results obtained showed that these pectinases are very effective for the treatment of strawberry juice in comparison with the commercial pectinase preparation Lafase Fruit.59th Meeting of the Serbian Chemical Society; June 1-2, 2023, Novi Sad, Serbi

Highly active endo-pectinases from Aspergillus tubingensis: A novel enzyme for fruit processing

Pectinases are a type of enzymes frequently used in the food industry to clarify, liquefy, and stabilize fruit juices. The main challenge in fruit juice production is the cloudiness of the juice, which is largely caused by the presence of pectic polysaccharides. Endo-pectinases are enzymes that hydrolyze the glycosidic bonds in pectic polymers. Commercial pectinolytic enzymes are typically produced by fungi, with Aspergillus spp. being the most commonly used. The aim of this research was the production and characterization of a novel endo-pectinase from the Aspergillus tubingensis strain for use in liquefying and clarifying different types of fruit juice. To accomplish this, solid-state fermentation was conducted on agricultural waste, such as sugar beet pulp and wheat bran, to produce pectinolytic enzymes. The resulting crude extract was concentrated via ultrafiltration and used to isolate the endo-pectinase via ammonium sulfate and ethanol precipitation methods. Ion-exchange chromatography technique on DEAE Sephadex A-25 matrix was used for further purification of the endo-pectinase. The purified enzyme was characterized by the determination of total pectinolytic activity, specific pectinolytic activity, and SDS-PAA gel electrophoresis. The activity of the endo-pectinase was confirmed by a diffusion test and zymography with Ruthenium Red visualization. The resulting enzyme was used to liquefy apricot, banana, apple, quince, strawberry, and orange pulp, with juice yields ranging from 71% to 83%, depending on the fruit used. The juices treated with endo-pectinase showed much higher clarification compared to untreated juices. Additionally, the treated juices demonstrated more pronounced antioxidant properties, as determined through the DPPH assay